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		The package <tt>xxl.core.cursors</tt> provides a whole algebra of cursors
		that extends the functionality of the classes
		{@link java.util.Iterator Iterator} and
		{@link java.util.Enumeration Enumeration}. A cursor is an abstract
		concept for manipulating objects within a stream. The cursors provided in
		XXL are independent from the specific structure of the objects as well
		as from the kind of storage representation of the underlying stream. This
		property is closely related to the notion of <i>physical independence</i>
		which is one of the key concepts of database systems. XXL offers an
		algebra of cursors which is suitable for defining complex queries in a
		declarative fashion similar to SQL. In addition, our cursor algebra is
		also beneficial for a very compact implementation of low-level core
		functionality (e.g. index structures).
		
		<p>This package provides the interfaces and some fundamental classes of
		XXL's cursor algebra whereas its concrete operators are arranged into
		subpackages. If you want to get an overview of this package (and its
		subpackages) please take a closer look to section 
		<a href=../../doc-files/vldb2001/vldb2001-node3.html>
			Cursors
		</a> 
		at our paper: 
		<a href=../../doc-files/vldb2001/vldb2001.html>
			XXL - A Library Approach to Supporting Efficient Implementations of 
			Advanced Database Queries
		</a>.
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